Protein purification, especially at industrial scales, can be laborious and expensive. Although the use of column chromatography to purify a protein is effective, it contributes substantially to the labor and expense of producing a pure protein, in part because of the large volumes of solutions necessary for column chromatography. Thus, methods of purification that do not depend on column chromatography and that can be performed in a low volume are commercially advantageous.
Some methods of protein purification require the modification of the protein to be purified, for example by adding a covalently-linked protein tag, to facilitate purification. In some situations, particularly for pharmaceutical use, such modifications may need to be removed subsequent to purification and prior to use because of unwanted effects on the final protein product.
It would therefore be desirable to develop methods for protein purification applicable to a wide variety of proteins that can minimize or eliminate both the need for column chromatography and the need to modify the protein being purified.